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llvm-mirror/utils/gdb-scripts/prettyprinters.py
Moritz Sichert 64b62b62ba Avoid fragile type lookups in GDB pretty printer
Instead of using the type llvm::StringMapEntry<{stringified_value_type}>
use only the base class llvm::StringMapEntryBase and calculate the
offsets of the member variables manually. The approach with stringifying
the name of the value type is pretty fragile as it can easily break with
local and dependent types.

Differential Revision: https://reviews.llvm.org/D94431
2021-01-22 14:56:32 +01:00

494 lines
15 KiB
Python

from __future__ import print_function
import struct
import sys
import gdb.printing
import gdb.types
class Iterator:
def __iter__(self):
return self
if sys.version_info.major == 2:
def next(self):
return self.__next__()
def children(self):
return self
def escape_bytes(val, l):
return '"' + val.string(encoding='Latin-1', length=l).encode('unicode_escape').decode() + '"'
class SmallStringPrinter:
"""Print an llvm::SmallString object."""
def __init__(self, val):
self.val = val
def to_string(self):
begin = self.val['BeginX']
return escape_bytes(begin.cast(gdb.lookup_type('char').pointer()), self.val['Size'])
class StringRefPrinter:
"""Print an llvm::StringRef object."""
def __init__(self, val):
self.val = val
def to_string(self):
return escape_bytes(self.val['Data'], self.val['Length'])
class SmallVectorPrinter(Iterator):
"""Print an llvm::SmallVector object."""
def __init__(self, val):
self.val = val
t = val.type.template_argument(0).pointer()
self.begin = val['BeginX'].cast(t)
self.size = val['Size']
self.i = 0
def __next__(self):
if self.i == self.size:
raise StopIteration
ret = '[{}]'.format(self.i), (self.begin+self.i).dereference()
self.i += 1
return ret
def to_string(self):
return 'llvm::SmallVector of Size {}, Capacity {}'.format(self.size, self.val['Capacity'])
def display_hint (self):
return 'array'
class ArrayRefPrinter:
"""Print an llvm::ArrayRef object."""
class _iterator:
def __init__(self, begin, end):
self.cur = begin
self.end = end
self.count = 0
def __iter__(self):
return self
def __next__(self):
if self.cur == self.end:
raise StopIteration
count = self.count
self.count = self.count + 1
cur = self.cur
self.cur = self.cur + 1
return '[%d]' % count, cur.dereference()
if sys.version_info.major == 2:
next = __next__
def __init__(self, val):
self.val = val
def children(self):
data = self.val['Data']
return self._iterator(data, data + self.val['Length'])
def to_string(self):
return 'llvm::ArrayRef of length %d' % (self.val['Length'])
def display_hint (self):
return 'array'
class ExpectedPrinter(Iterator):
"""Print an llvm::Expected object."""
def __init__(self, val):
self.val = val
def __next__(self):
val = self.val
if val is None:
raise StopIteration
self.val = None
if val['HasError']:
return ('error', val['ErrorStorage'].address.cast(
gdb.lookup_type('llvm::ErrorInfoBase').pointer()).dereference())
return ('value', val['TStorage'].address.cast(
val.type.template_argument(0).pointer()).dereference())
def to_string(self):
return 'llvm::Expected{}'.format(' is error' if self.val['HasError'] else '')
class OptionalPrinter(Iterator):
"""Print an llvm::Optional object."""
def __init__(self, val):
self.val = val
def __next__(self):
val = self.val
if val is None:
raise StopIteration
self.val = None
if not val['Storage']['hasVal']:
raise StopIteration
return ('value', val['Storage']['value'])
def to_string(self):
return 'llvm::Optional{}'.format('' if self.val['Storage']['hasVal'] else ' is not initialized')
class DenseMapPrinter:
"Print a DenseMap"
class _iterator:
def __init__(self, key_info_t, begin, end):
self.key_info_t = key_info_t
self.cur = begin
self.end = end
self.advancePastEmptyBuckets()
self.first = True
def __iter__(self):
return self
def advancePastEmptyBuckets(self):
# disabled until the comments below can be addressed
# keeping as notes/posterity/hints for future contributors
return
n = self.key_info_t.name
is_equal = gdb.parse_and_eval(n + '::isEqual')
empty = gdb.parse_and_eval(n + '::getEmptyKey()')
tombstone = gdb.parse_and_eval(n + '::getTombstoneKey()')
# the following is invalid, GDB fails with:
# Python Exception <class 'gdb.error'> Attempt to take address of value
# not located in memory.
# because isEqual took parameter (for the unsigned long key I was testing)
# by const ref, and GDB
# It's also not entirely general - we should be accessing the "getFirst()"
# member function, not the 'first' member variable, but I've yet to figure
# out how to find/call member functions (especially (const) overloaded
# ones) on a gdb.Value.
while self.cur != self.end and (is_equal(self.cur.dereference()['first'], empty) or is_equal(self.cur.dereference()['first'], tombstone)):
self.cur = self.cur + 1
def __next__(self):
if self.cur == self.end:
raise StopIteration
cur = self.cur
v = cur.dereference()['first' if self.first else 'second']
if not self.first:
self.cur = self.cur + 1
self.advancePastEmptyBuckets()
self.first = True
else:
self.first = False
return 'x', v
if sys.version_info.major == 2:
next = __next__
def __init__(self, val):
self.val = val
def children(self):
t = self.val.type.template_argument(3).pointer()
begin = self.val['Buckets'].cast(t)
end = (begin + self.val['NumBuckets']).cast(t)
return self._iterator(self.val.type.template_argument(2), begin, end)
def to_string(self):
return 'llvm::DenseMap with %d elements' % (self.val['NumEntries'])
def display_hint(self):
return 'map'
class StringMapPrinter:
"Print a StringMap"
def __init__(self, val):
self.val = val
def children(self):
it = self.val['TheTable']
end = (it + self.val['NumBuckets'])
value_ty = self.val.type.template_argument(0)
entry_base_ty = gdb.lookup_type('llvm::StringMapEntryBase')
tombstone = gdb.parse_and_eval('llvm::StringMapImpl::TombstoneIntVal');
while it != end:
it_deref = it.dereference()
if it_deref == 0 or it_deref == tombstone:
it = it + 1
continue
entry_ptr = it_deref.cast(entry_base_ty.pointer())
entry = entry_ptr.dereference()
str_len = entry['keyLength']
value_ptr = (entry_ptr + 1).cast(value_ty.pointer())
str_data = (entry_ptr + 1).cast(gdb.lookup_type('uintptr_t')) + max(value_ty.sizeof, entry_base_ty.alignof)
str_data = str_data.cast(gdb.lookup_type('char').const().pointer())
string_ref = gdb.Value(struct.pack('PN', int(str_data), int(str_len)), gdb.lookup_type('llvm::StringRef'))
yield 'key', string_ref
value = value_ptr.dereference()
yield 'value', value
it = it + 1
def to_string(self):
return 'llvm::StringMap with %d elements' % (self.val['NumItems'])
def display_hint(self):
return 'map'
class TwinePrinter:
"Print a Twine"
def __init__(self, val):
self._val = val
def display_hint(self):
return 'string'
def string_from_pretty_printer_lookup(self, val):
'''Lookup the default pretty-printer for val and use it.
If no pretty-printer is defined for the type of val, print an error and
return a placeholder string.'''
pp = gdb.default_visualizer(val)
if pp:
s = pp.to_string()
# The pretty-printer may return a LazyString instead of an actual Python
# string. Convert it to a Python string. However, GDB doesn't seem to
# register the LazyString type, so we can't check
# "type(s) == gdb.LazyString".
if 'LazyString' in type(s).__name__:
s = s.value().address.string()
else:
print(('No pretty printer for {} found. The resulting Twine ' +
'representation will be incomplete.').format(val.type.name))
s = '(missing {})'.format(val.type.name)
return s
def is_twine_kind(self, kind, expected):
if not kind.endswith(expected):
return False
# apparently some GDB versions add the NodeKind:: namespace
# (happens for me on GDB 7.11)
return kind in ('llvm::Twine::' + expected,
'llvm::Twine::NodeKind::' + expected)
def string_from_child(self, child, kind):
'''Return the string representation of the Twine::Child child.'''
if self.is_twine_kind(kind, 'EmptyKind') or self.is_twine_kind(kind, 'NullKind'):
return ''
if self.is_twine_kind(kind, 'TwineKind'):
return self.string_from_twine_object(child['twine'].dereference())
if self.is_twine_kind(kind, 'CStringKind'):
return child['cString'].string()
if self.is_twine_kind(kind, 'StdStringKind'):
val = child['stdString'].dereference()
return self.string_from_pretty_printer_lookup(val)
if self.is_twine_kind(kind, 'StringRefKind'):
val = child['stringRef'].dereference()
pp = StringRefPrinter(val)
return pp.to_string()
if self.is_twine_kind(kind, 'SmallStringKind'):
val = child['smallString'].dereference()
pp = SmallStringPrinter(val)
return pp.to_string()
if self.is_twine_kind(kind, 'CharKind'):
return chr(child['character'])
if self.is_twine_kind(kind, 'DecUIKind'):
return str(child['decUI'])
if self.is_twine_kind(kind, 'DecIKind'):
return str(child['decI'])
if self.is_twine_kind(kind, 'DecULKind'):
return str(child['decUL'].dereference())
if self.is_twine_kind(kind, 'DecLKind'):
return str(child['decL'].dereference())
if self.is_twine_kind(kind, 'DecULLKind'):
return str(child['decULL'].dereference())
if self.is_twine_kind(kind, 'DecLLKind'):
return str(child['decLL'].dereference())
if self.is_twine_kind(kind, 'UHexKind'):
val = child['uHex'].dereference()
return hex(int(val))
print(('Unhandled NodeKind {} in Twine pretty-printer. The result will be '
'incomplete.').format(kind))
return '(unhandled {})'.format(kind)
def string_from_twine_object(self, twine):
'''Return the string representation of the Twine object twine.'''
lhs_str = ''
rhs_str = ''
lhs = twine['LHS']
rhs = twine['RHS']
lhs_kind = str(twine['LHSKind'])
rhs_kind = str(twine['RHSKind'])
lhs_str = self.string_from_child(lhs, lhs_kind)
rhs_str = self.string_from_child(rhs, rhs_kind)
return lhs_str + rhs_str
def to_string(self):
return self.string_from_twine_object(self._val)
def get_pointer_int_pair(val):
"""Get tuple from llvm::PointerIntPair."""
info_name = val.type.template_argument(4).strip_typedefs().name
# Note: this throws a gdb.error if the info type is not used (by means of a
# call to getPointer() or similar) in the current translation unit.
enum_type = gdb.lookup_type(info_name + '::MaskAndShiftConstants')
enum_dict = gdb.types.make_enum_dict(enum_type)
ptr_mask = enum_dict[info_name + '::PointerBitMask']
int_shift = enum_dict[info_name + '::IntShift']
int_mask = enum_dict[info_name + '::IntMask']
pair_union = val['Value']
pointer = (pair_union & ptr_mask)
value = ((pair_union >> int_shift) & int_mask)
return (pointer, value)
class PointerIntPairPrinter:
"""Print a PointerIntPair."""
def __init__(self, pointer, value):
self.pointer = pointer
self.value = value
def children(self):
yield ('pointer', self.pointer)
yield ('value', self.value)
def make_pointer_int_pair_printer(val):
"""Factory for an llvm::PointerIntPair printer."""
try:
pointer, value = get_pointer_int_pair(val)
except gdb.error:
return None # If PointerIntPair cannot be analyzed, print as raw value.
pointer_type = val.type.template_argument(0)
value_type = val.type.template_argument(2)
return PointerIntPairPrinter(pointer.cast(pointer_type),
value.cast(value_type))
class PointerUnionPrinter:
"""Print a PointerUnion."""
def __init__(self, pointer):
self.pointer = pointer
def children(self):
yield ('pointer', self.pointer)
def to_string(self):
return "Containing %s" % self.pointer.type
def make_pointer_union_printer(val):
"""Factory for an llvm::PointerUnion printer."""
try:
pointer, value = get_pointer_int_pair(val['Val'])
except gdb.error:
return None # If PointerIntPair cannot be analyzed, print as raw value.
pointer_type = val.type.template_argument(int(value))
return PointerUnionPrinter(pointer.cast(pointer_type))
class IlistNodePrinter:
"""Print an llvm::ilist_node object."""
def __init__(self, val):
impl_type = val.type.fields()[0].type
base_type = impl_type.fields()[0].type
derived_type = val.type.template_argument(0)
def get_prev_and_sentinel(base):
# One of Prev and PrevAndSentinel exists. Depending on #defines used to
# compile LLVM, the base_type's template argument is either true of false.
if base_type.template_argument(0):
return get_pointer_int_pair(base['PrevAndSentinel'])
return base['Prev'], None
# Casts a base_type pointer to the appropriate derived type.
def cast_pointer(pointer):
sentinel = get_prev_and_sentinel(pointer.dereference())[1]
pointer = pointer.cast(impl_type.pointer())
if sentinel:
return pointer
return pointer.cast(derived_type.pointer())
# Repeated cast becaue val.type's base_type is ambiguous when using tags.
base = val.cast(impl_type).cast(base_type)
(prev, sentinel) = get_prev_and_sentinel(base)
prev = prev.cast(base_type.pointer())
self.prev = cast_pointer(prev)
self.next = cast_pointer(val['Next'])
self.sentinel = sentinel
def children(self):
if self.sentinel:
yield 'sentinel', 'yes'
yield 'prev', self.prev
yield 'next', self.next
class IlistPrinter:
"""Print an llvm::simple_ilist or llvm::iplist object."""
def __init__(self, val):
self.node_type = val.type.template_argument(0)
sentinel = val['Sentinel']
# First field is common base type of sentinel and ilist_node.
base_type = sentinel.type.fields()[0].type
self.sentinel = sentinel.address.cast(base_type.pointer())
def _pointers(self):
pointer = self.sentinel
while True:
pointer = pointer['Next'].cast(pointer.type)
if pointer == self.sentinel:
return
yield pointer.cast(self.node_type.pointer())
def children(self):
for k, v in enumerate(self._pointers()):
yield ('[%d]' % k, v.dereference())
pp = gdb.printing.RegexpCollectionPrettyPrinter("LLVMSupport")
pp.add_printer('llvm::SmallString', '^llvm::SmallString<.*>$', SmallStringPrinter)
pp.add_printer('llvm::StringRef', '^llvm::StringRef$', StringRefPrinter)
pp.add_printer('llvm::SmallVectorImpl', '^llvm::SmallVector(Impl)?<.*>$', SmallVectorPrinter)
pp.add_printer('llvm::ArrayRef', '^llvm::(Mutable)?ArrayRef<.*>$', ArrayRefPrinter)
pp.add_printer('llvm::Expected', '^llvm::Expected<.*>$', ExpectedPrinter)
pp.add_printer('llvm::Optional', '^llvm::Optional<.*>$', OptionalPrinter)
pp.add_printer('llvm::DenseMap', '^llvm::DenseMap<.*>$', DenseMapPrinter)
pp.add_printer('llvm::StringMap', '^llvm::StringMap<.*>$', StringMapPrinter)
pp.add_printer('llvm::Twine', '^llvm::Twine$', TwinePrinter)
pp.add_printer('llvm::PointerIntPair', '^llvm::PointerIntPair<.*>$', make_pointer_int_pair_printer)
pp.add_printer('llvm::PointerUnion', '^llvm::PointerUnion<.*>$', make_pointer_union_printer)
pp.add_printer('llvm::ilist_node', '^llvm::ilist_node<.*>$', IlistNodePrinter)
pp.add_printer('llvm::iplist', '^llvm::iplist<.*>$', IlistPrinter)
pp.add_printer('llvm::simple_ilist', '^llvm::simple_ilist<.*>$', IlistPrinter)
gdb.printing.register_pretty_printer(gdb.current_objfile(), pp)